Organic electroluminescent display device and method of manufacturing the same

ABSTRACT

A substrate on which a plurality of pixel electrodes are disposed is prepared. An organic electroluminescent film  22  is formed with the inclusion of a common layer that continuously covers the plural pixel electrodes. A common electrode is formed on the organic electroluminescent film. The common layer is irradiated with an energy ray above areas between the respective adjacent pixel electrodes with the avoidance of irradiation above the plural pixel electrodes. An electric conductivity of the common layer is reduced above the areas between the respective adjacent pixel electrodes, by irradiation of the energy ray. With this configuration, a current leakage can be prevented between the adjacent pixels.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priorities from Japanese applicationJP2013-186146 filed on Sep. 9, 2013, and Japanese applicationJP2013-186175 filed on Sep. 9, 2013, the contents of which are herebyincorporated by reference into this application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an organic electroluminescent displaydevice and a method of manufacturing the display device.

2. Description of the Related Art

An organic electroluminescent display device has a structure in which anorganic film is sandwiched between an anode and a cathode. Normally,plural organic films are laminated on each other, and include a lightemitting layer as one layer. In order to obtain light emission of onecolor (for example, white) in plural pixels, the organic film formingthe light emitting layer is wholly continuously disposed. Alternatively,in order to obtain light emission of plural colors in the plural pixels,the organic film forming the light emitting layer is separated for eachof the pixels, but the organic film forming a hole injection layer, anelectron injection layer, a hole transport layer, or an electrontransport layer is continuously disposed. Even in any case, at least oneorganic film is continuously disposed over the adjacent pixels.

SUMMARY OF THE INVENTION

In the display device of high quality, the adjacent pixels come closerto each other with the miniaturization of the pixels. For that reason, acurrent may leak from an electrode of any pixel to adjacent pixelsthrough the continuous organic film. There arises such a problem thatthe current leakage causes the adjacent pixels to emit light.

JP 2009-88320 A discloses a method of preventing a current leakage.However, the method relates to the prevention of a current leakagebetween an anode and a cathode in one pixel, which is different from, aproblem to be solved by the present invention. Also, JP 2010-212177 Aand JP 2006-140145 A disclose that a surface of a partition (or aninsulating film) is roughened, but fail to disclose an organic filmformed on the partition. Therefore, there is no solution to the problemon the current leakage.

An object of the present invention is to prevent a current leakagebetween the adjacent pixels.

(1) According to the present invention, there is provided a method ofmanufacturing an organic electroluminescent display device, includingthe steps of: preparing a substrate on which a plurality of pixelelectrodes are disposed; forming an organic electroluminescent film withthe inclusion of a common layer that continuously covers the pluralityof pixel electrodes; forming a common electrode on the organicelectroluminescent film; and irradiating the common layer with an energyray above areas between the respective adjacent pixel electrodes withthe avoidance of irradiation above the organic electroluminescent film,in which an electric conductivity of the common layer is reduced abovethe areas between the respective adjacent pixel electrodes, byirradiation of the energy ray. According to the present invention, sincethe electric conductivity of the common layer of the organicelectroluminescent film becomes lower above the areas between therespective adjacent pixel electrodes, the current leakage between theadjacent pixels can be prevented.

(2) The method of manufacturing an organic electroluminescent displaydevice according to the item (1), may further include the step of:forming an insulating layer in the areas between the respective adjacentpixel electrodes so as to rest on ends of the respective pixelelectrodes, in which the organic electroluminescent film may be formedto rest on the insulating layer.

(3) In the method of manufacturing an organic electroluminescent displaydevice according to the item (1) or (2), the common layer may beirradiated with the energy ray before forming the common electrode.

(4) In the method of manufacturing an organic electroluminescent displaydevice according to the item (1) or (2), the energy ray may be allowedto pass through the common electrode, and applied to the common layerafter forming the common electrode.

(5) The method of manufacturing an organic electroluminescent displaydevice according to the item (1) or (2) may further include the step offorming a sealing film on the common electrode, in which the energy raymay be allowed to pass through the sealing film and the commonelectrode, and applied to the common layer after forming the sealingfilm.

(6) In the method of manufacturing an organic electroluminescent displaydevice according to any one of the items (1) to (5), the energy ray maybe applied through a mask, and the mask may have a pattern that allowsthe energy ray to pass above the areas between the respective adjacentpixel electrodes with the avoidance of the energy ray from passingtherethrough above the plurality of pixel electrodes.

(7) The method of manufacturing an organic electroluminescent displaydevice according to any one of the items (1) to (5) may further includethe step of forming a mask layer that prevents the energy ray frompassing therethrough above the organic electroluminescent film, in whichthe energy ray may be applied through a pattern of the mask layer, andthe pattern of the mask layer may allow the energy ray to pass above theareas between the respective adjacent pixel electrodes with theavoidance of the energy ray from passing there through above theplurality of pixel electrodes.

(8) According to the present invention, there is provided an organicelectroluminescent display device, including: a substrate; a pluralityof pixel electrodes that are disposed on the substrate; an organicelectroluminescent film that is disposed on the substrate with theinclusion of a common layer which continuously covers the plurality ofpixel electrodes; and a common electrode that is disposed on the organicelectroluminescent film, in which the common layer has low conductiveportions lower in electric conductivity than portions above theplurality of pixel electrodes, above the areas between the respectiveadjacent pixel electrodes. According to the present invention, since thecommon layer of the organic electroluminescent film is lower in electricconductivity above the areas between the respective adjacent pixelelectrodes, the current leakage between the adjacent pixel electrodescan be prevented.

(9) According to the present invention, there is provided an organicelectro luminescent display device, including: a substrate; a pluralityof pixel electrodes that are disposed on the substrate; an insulatinglayer that is disposed in areas between the respective adjacent pixelelectrodes so as to rest on ends of the respective pixel electrodes; anorganic electroluminescent film that is disposed on the substrate withthe inclusion of a common layer which continuously covers the pluralityof pixel electrodes, and the insulating layer; and a common electrodethat is disposed over the organic electroluminescent film, in which theinsulating layer has an upper surface with a concavo-convex shape havinga plurality of concave portions and a plurality of convex portions, inwhich the common layer includes an upper portion that rests on therespective convex portions of the concavo-convex shape, and a lowerportion that rests on the respective concave portions thereof, and inwhich the upper portion and the lower portion are offset vertically fromeach other, and at least parts of the upper potion and the lower portionin a thickness direction are discontinuous, from each other, and athickness of the common layer is partially thinned to increase anelectric resistance. According to the present invention, the thicknessof the common layer is partially thinned to increase the electricresistance above the areas between the respective adjacent pixelelectrodes. With the above configuration, a current can be preventedfrom passing through the common layer, and being leaked between theadjacent pixel electrodes.

(10) In the organic electroluminescent display device according to theitem (9), the respective parts of the upper portion and the lowerportion in the thickness direction may be continuous to each other.

(11) In the organic electroluminescent display device according to theitem (9), the upper portion and the lower portion may be separated fromeach other.

(12) In the organic electroluminescent display device according to anyone of the items (9) to (11), bottom surfaces of the plurality ofconcave portions may be arrayed along one plane, and upper surfaces ofthe plurality of convex portions may be arrayed along another plane.

(13) In the organic electroluminescent display device according to anyone of the items (9) to (11), bottom surfaces of the plurality ofconcave portions may be arrayed along one convex curve, and uppersurfaces of the plurality of convex portions may be arrayed alonganother convex curve.

(14) In the organic electroluminescent display device according to anyone of the items (9) to (13), the plurality of pixel electrodes may bearrayed in a longitudinal direction and a lateral direction, a planarshape of the respective pixel electrodes may be elongated in onedirection with a long axis and a short axis, respective short sidesalong the short axis may be adjacent to each other in the pixelelectrodes adjacent to each other in the longitudinal direction,respective long sides along the long axis may be adjacent to each otherin the pixel electrodes adjacent to each other in the lateral direction,and the plurality of concave portions and the plurality of convexportions in the insulating layer may be formed in areas between theadjacent long-sides with the avoidance of areas between the adjacentshort sides.

(15) According to the present invention, there is provided a method ofmanufacturing an organic electroluminescent display device, includingthe steps of: preparing a substrate on which a plurality of pixelelectrodes are disposed; forming an insulating layer in areas betweenthe respective adjacent pixel electrodes so as to rest on ends of therespective pixel electrodes; forming an organic electroluminescent filmon the substrate with the inclusion of a common layer that continuouslycovers the plurality of pixel electrodes and the insulating layer; andforming a common electrode on the organic electroluminescent film, inwhich the insulating layer has an upper surface with a concavo-convexshape having a plurality of concave portions and a plurality of convexportions, in which the common layer includes an upper portion that restson the respective convex portions of the concavo-convex, shape, and alower portion that rests on the respective concave portions thereof, andin which the upper portion and the lower portion are offset verticallyfrom each other, and at least parts of the upper potion and the lowerportion in a thickness direction are discontinuous from each other, anda thickness of the common layer is partially thinned to increase anelectric resistance. According to the present invention, the thicknessof the common layer is partially thinned above the areas between therespective adjacent pixel electrodes to increase the electricresistance. With the above configuration, a current can be preventedfrom passing through the common layer, and being leaked between theadjacent pixel electrodes.

(16) In the method of manufacturing an organic electroluminescentdisplay device according to the item (15), the step of forming theinsulating layer having the upper surface with the concavo-convex shapemay include the steps of: providing an insulating material; and givingthe concavo-convex shape to the insulating material by nanoimprint.

(17) In the method of manufacturing an organic electroluminescentdisplay device according to the item (16), the step of forming theinsulating layer having the upper surface with the concavo-convex shapemay include the steps of: providing the insulating material to cover theplurality of pixel electrodes; and partially removing the insulatingmaterial from above at least a center portion of the respective pixelelectrodes after the step of giving the concavo-convex shape.

(18) In the method of manufacturing an organic electroluminescentdisplay device according to the item (17), the step of partiallyremoving the insulating material may be conducted by at least one ofphotolithography and dry etching.

(19) In the method of manufacturing an organic electroluminescentdisplay device according to the item (17), the insulating material maybe recessed and thinned, by the nanoimprint, above at least the centerportion of the respective pixel electrodes in the step of giving theconcavo-convex shape.

(20) In the method of manufacturing an organic electroluminescentdisplay device according to the item (19), the step of partiallyremoving the insulating material may be conducted by dry etching.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an organic electroluminescent displaydevice according to a first embodiment of the present invention;

FIG. 2 is a schematic cross-sectional view taken along a line II-II ofthe organic electroluminescent display device illustrated in FIG. 1;

FIG. 3 is a diagram illustrating a method of manufacturing the organicelectroluminescent display device according to the first embodiment;

FIG. 4 is a diagram illustrating a method of manufacturing an organicelectroluminescent display device according to a modification 1 of thefirst embodiment;

FIG. 5 is a diagram illustrating a method of manufacturing an organicelectroluminescent display device according to a modification 2 of thefirst embodiment;

FIG. 6 is a diagram illustrating a method of manufacturing an organicelectroluminescent display device according to a modification 3 of thefirst embodiment;

FIG. 7 is a diagram illustrating a method of manufacturing an organicelectroluminescent display device according to a modification 4 of thefirst embodiment;

FIG. 8 is a perspective view of an organic electroluminescent displaydevice according to a second embodiment of the present invention;

FIG. 9 is a schematic cross-sectional view taken along a line IX-IX ofthe organic electroluminescent display device illustrated in FIG. 8;

FIG. 10 is a plan view illustrating an array of plural pixel electrodes;

FIG. 11 is a diagram illustrating a method of manufacturing the organicelectroluminescent display device according to the second embodiment ofthe present invention;

FIG. 12 is a diagram illustrating a method of manufacturing the organicelectroluminescent display device according to the second embodiment ofthe present invention;

FIG. 13 is a diagram illustrating a method of manufacturing the organicelectroluminescent display device according to the second embodiment ofthe present invention;

FIG. 14 is a diagram illustrating a method of manufacturing the organicelectroluminescent display device according to the second embodiment ofthe present invention;

FIG. 15 is a cross-sectional view of an organic electroluminescentdisplay device according to a third embodiment of the present invention;

FIG. 16 is a diagram illustrating a method of manufacturing the organicelectroluminescent display device according to the third embodiment ofthe present invention;

FIG. 17 is a diagram illustrating a method of manufacturing the organicelectroluminescent display device according to the third embodiment ofthe present invention; and

FIG. 18 is a diagram illustrating a modification of the thirdembodiment.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter embodiments of the present invention will be described withreference to the accompanying drawings. FIG. 1 is a perspective view ofan organic electroluminescent display device according to a firstembodiment of the present invention. FIG. 2 is a schematiccross-sectional view taken along a line II-II of the organicelectroluminescent display device illustrated in FIG. 1.

As illustrated in FIG. 1, the organic electroluminescent display deviceincludes a first substrate 10 having an optical transparency made ofglass or the like. The first substrate 10 has an image display area forimage display. An integrated circuit chip 12 for driving an element fordisplaying an image is mounted on the first substrate 10. A flexiblewiring substrate 14 is connected to the first substrate 10 for electricconnection with an external.

As illustrated in FIG. 2, a circuit layer 16 is disposed on the firstsubstrate 10. The circuit layer 16 includes lines, thin filmtransistors, and an insulating film not shown. Plural pixel electrodes18 are disposed on the first substrate 10 (on the circuit layer 16 inthe example of FIG. 2). The pixel electrodes 18 are anodes. Aninsulating layer 20 is disposed in areas between the respective adjacentpixel electrodes 18 so as to rest on ends of the respective pixelelectrodes 18. The insulating layer 20 is configured to surroundperipheral portions of the respective pixel electrodes 18.

An organic electroluminescent film 22 is disposed over the firstsubstrate 10. The organic electroluminescent film 22 is configured torest on the plural pixel electrodes 18 and the insulating layer 20. Theorganic electroluminescent film 22 is formed of plural layers althoughnot shown, includes at least, a light emitting layer, and also includesat least one layer of an electron transport layer, a hole transportlayer, an electron injection layer, and a hole injection layer. Thelight emitting layer is configured to emit only light of one color (forexample, white).

The organic electroluminescent film 22 includes a common layer 24 thatcontinuously covers the plural pixel electrodes 18. In the example ofFIG. 2, the overall organic electroluminescent film 22 is formed of thecommon layer 24. Alternatively, at least one layer (except for at leastone layer) of the organic electroluminescent film 22 including theplural layers is the common layer 24 (for example, the electroninjection layer), and the remaining layers including at least one layermay be cut for each of the pixel electrodes 18. In the organicelectroluminescent film with a tandem structure including two or morelight emitting layers, a charge generation layer for supplying electronsand holes which is arranged between the respective adjacent lightemitting layers may be configured by the common layer.

The common layer 24 has low conductive portions 26 lower in electricconductivity than portions above the plural pixel electrodes 18, abovethe areas between the respective adjacent pixel electrodes 18. Theprovision of the low conductive portions 26 makes it difficult thatcarriers (electrons or holes) flow in a spread direction of the commonlayer 24. Since the low conductive portions 26 are disposed over theinsulating layer 20, the carriers are prevented from flowing in thespread direction of the common layer 24 above the insulating layer 20.On the contrary, in portions of the common layer 24 above the pluralpixel electrodes 18 (portions except for the low conductive portions26), a current flows in the thickness direction and the spread directionof the common layer 24.

A common electrode 28 is disposed on the organic electroluminescent film22. The common electrode 28 is a cathode. A voltage is applied to thepixel electrodes 18 and the common electrode 28 to inject holes andelectrons into the organic electroluminescent film 22 from the pixelelectrodes 18 and the common electrode 28. The injected holes andelectrons are coupled with each other in the light emitting layer toemit light. Since the insulating layer 20 is interposed between the endsof the respective pixel electrodes 18 and the common electrode 28,short-circuiting is prevented between the respective pixel electrodes 18and the common electrode 28.

According to this embodiment, since the common layer 24 of the organicelectroluminescent film 22 is lower in the electric conductivity abovethe areas between the respective pixel electrodes 18, the currentleakage can be prevented between the adjacent pixels. Therefore, pixelsadjacent to a pixel into which a current flows emit no light.

A sealing film 42 is disposed on the common electrode 28. The sealingfilm 42 seals the organic electroluminescent film 22 so as to blockmoisture. A filter layer 38 is disposed on the sealing film 42.

A second substrate 30 is arranged to face the first substrate 10 with agap. A color filter layer 32 is disposed on a surface of the secondsubstrate 30 on the first substrate 10 side. The color filter layer 32includes a black matrix 34 and a colored layer 36. Since the lightemitting layer (not shown) of the above-mentioned organicelectroluminescent film 22 emits a single color (for example, white),the provision of the color filter layer 32 enables full color display inthis embodiment. When the organic electroluminescent film 22 includesplural light emitting layers that emit respective different colors (forexample, red, green, and blue), the light emitting layer emits the lightof plural colors, thereby making the colored layer 36 unnecessary. Thefilter layer 38 is disposed, between the first substrate 10 and thesecond substrate 30.

FIG. 3 is a diagram illustrating a method of manufacturing the organicelectroluminescent display device according to the first embodiment ofthe present, invention.

In this embodiment, the first substrate 10 on which the plural pixelelectrodes 18 are disposed is prepared. The insulating layer 20 isformed in the areas between the respective adjacent pixel electrodes 18so as to rest on the ends of the respective pixel electrodes 18. Theorganic electroluminescent film 22 is formed with the inclusion of thecommon layer 24 that continuously covers the plural pixel electrodes 18.The organic electroluminescent film 22 is formed to rest, on theinsulating layer 20. The organic electroluminescent film 22 is formed byvapor deposition or sputtering.

Then, the common layer 24 is irradiated with an energy ray (ultravioletray, electron ray, infrared ray, etc.). The energy-ray is applied abovethe areas (insulating layer 20) between the respective adjacent pixelelectrodes 18 with the avoidance of upsides of the plural pixelelectrodes 18. With the irradiation of the energy ray, the electricconductivity of the common layer 24 is reduced above the areas betweenthe respective adjacent pixel electrodes 18. As a result, the lowconductive portions 26 are formed in the common layer 24.

The energy ray is applied through a mask 40. The mask. 40 has a patternhaving ribs and openings. The pattern prevents the energy ray energy rayfrom passing therethrough above the plural pixel electrodes 18, andallows the energy ray to pass above the areas between the respectiveadjacent pixel electrodes 18. Alternatively, the mask 40 is unnecessaryif laser scanning using a laser beam is applied.

Subsequently, as illustrated in FIG. 2, the common electrode 28 isformed on the organic electroluminescent film 22. The common electrode28 is formed after the common layer 24 has been irradiated with theenergy ray. Since the energy ray is applied before the formation of thecommon electrode 28, a loss of irradiation energy is low.

According to this embodiment, since the common layer 24 of the organicelectroluminescent film 22 becomes low in the electric conductivityabove the areas between the respective adjacent pixel electrodes 18, thecurrent leakage can be prevented between the respective adjacent pixels.

FIG. 4 is a diagram illustrating a method of manufacturing an organicelectroluminescent display device according to a modification 1 of thefirst embodiment of the present invention. In this example, the commonlayer 24 is irradiated with the energy ray after the common electrode 28has been formed. The energy ray is allowed to pass through the commonelectrode 28.

FIG. 5 is a diagram illustrating a method of manufacturing an organicelectroluminescent display device according to a modification 2 of thefirst embodiment of the present invention. In this example, the sealingfilm 42 is formed on the common electrode 28. Then, after the sealingfilm 42 has been formed, the energy ray is allowed to pass through thesealing film 42 and the common electrode 28, and applied to the commonlayer 24. With this configuration, the sealing film 42 can prevent theincorporation of foreign matter.

FIG. 6 is a diagram illustrating a method of manufacturing an organicelectroluminescent display device according to a modification 3 of thefirst embodiment of the present invention. In this example, the sealingfilm 42 is formed on the common electrode 28, and a mask layer 44 isformed on the sealing film 42 (above the organic electroluminescent film22). The mask layer 44 is made of, for example, titanium, oxide, andmade of a material that prevents the energy ray from passingtherethrough. The energy ray is applied through a pattern of the masklayer 44. The pattern of the mask layer 44 prevents the energy ray frompassing therethrough above the plural pixel electrodes 18, and allowsthe energy ray to pass above the areas between the respective adjacentpixel electrodes 18.

FIG. 7 is a diagram illustrating a method of manufacturing an organicelectroluminescent display device according to a modification 4 of thefirst embodiment of the present invention. In this example, the masklayer 44 is formed on the common electrode 28 (above the organicelectroluminescent film 22), and the sealing film 42 is formed on themask layer 44. The mask layer 44 is made of, for example, titaniumoxide, and prevents the energy ray to pass therethrough. The energy rayis applied, through the sealing film 42 and the mask layer 44. Thepattern of the mask layer 44 prevents the energy ray from passingtherethrough above the plural pixel electrodes 18, and allows the energyray to pass therethrough above the areas between the respective adjacentpixel electrodes 18.

FIG. 8 is a perspective view of an organic electroluminescent displaydevice according to a second embodiment of the present invention. FIG. 9is a schematic cross-sectional view taken along a line IX-IX of theorganic electroluminescent display device illustrated in FIG. 8.

As illustrated in FIG. 8, the organic electroluminescent display deviceincludes a first substrate 110 having an optical transparency made ofglass or the like. The first substrate 110 has an image display area forimage display. An integrated circuit chip) 112 for driving an elementfor displaying an image is mounted on the first substrate 110. Aflexible wiring substrate 114 is connected to the first substrate 110for electric connection with an external.

As illustrated in FIG. 9, a circuit layer 116 is disposed on the firstsubstrate 110. The circuit layer 116 includes lines, thin filmtransistors, an insulating film and the like not shown. Plural pixelelectrodes 118 are disposed on the first substrate 110 (on the circuitlayer 116 in the example of FIG. 9). The pixel electrodes 118 areanodes.

FIG. 10 is a plan view illustrating an array of the plural pixelelectrode 118. The plural pixel electrodes 118 are arrayed in alongitudinal direction and a lateral direction. A planar shape of therespective pixel electrodes 118 is elongated in one direction with along axis and a short axis. In the pixel electrodes 118 adjacent to eachother in the longitudinal direction, the respective short sides areadjacent to each other along the short axis. In the pixel electrodes 118adjacent to each other in the lateral direction, the respective longsides are adjacent to each other along the long axis. The pixelelectrodes 118 are electrically connected to lines not shown of thecircuit layer 116 by contacts 120.

As illustrated in FIG. 9, an insulating layer 122 is disposed in theareas between the respective adjacent pixel electrodes 118 so as to reston ends of the respective pixel electrodes 118. The insulating layer 122is configured to surround the peripheries of the respective pixelelectrodes 118. In other words, the insulating layer 122 has openings122 a that expose the center portions of the pixel electrodes 118 (referto FIG. 10).

The insulating layer 122 has an upper surface with a concavo-convexshape having plural, concave portions 124 and plural, convex portions126. The concavo-convex shape is formed on a convex curve. Therefore,bottom surfaces of the plural concave portions 124 are arrayed along oneconvex curve, and upper surfaces of the plural convex portions 126 arearrayed along another convex curve. As illustrated in FIG. 10, theplural concave portions 124 and the plural convex portions 126 of theinsulating layer 122 are formed in areas 128 between, the respectiveadjacent long sides with the avoidance of areas between the respectiveadjacent short sides.

An organic electroluminescent film. 130 is disposed, over the firstsubstrate 110. The organic electroluminescent film 130 is configured torest on the plural, pixel electrodes 118 and the insulating layer 122.The organic electroluminescent film 130 is formed of plural layersalthough not shown, includes at least a light emitting layer, and alsoincludes at least one layer of an electron transport layer, a holetransport layer, an electron injection layer, and a hole injectionlayer. The light emitting layer is configured to emit only light of onecolor (for example, white).

The organic electroluminescent film 130 includes a common layer 132 thatcontinuously covers the plural pixel electrodes 118 and the insulatinglayer 122. In the example of FIG. 9, the overall organicelectroluminescent film 130 is formed of the common layer 132.Alternatively, at least one layer (except for at least one layer) of theorganic electroluminescent film 130 including the plural layers is thecommon layer 132 (for example, the electron injection layer), and theremaining layers including at least one layer may be cut for each of thepixel electrodes 118. In the organic electroluminescent film 130 with atandem structure including two or more light emitting layers, a chargegeneration layer for supplying electrons and holes which is arrangedbetween the respective adjacent light emitting layers may be configuredby the common layer 132.

The common layer 132 includes an upper portion 134 that rests on therespective convex portions 126 of the concavo-convex shape of theinsulating layer 122, and a lower portion 136 that rests on therespective concave portions 124 thereof. The upper portion 134 and thelower portion 136 are offset vertically from each other. Parts of theupper portion 134 and the lower portion 136 in the thickness directionthereof are continuous in the lateral direction, but at least parts ofthe upper potion 134 and the lower portion 136 in the thicknessdirection thereof are discontinuous from each other in the lateraldirection, to thereby form steps. With the formation of the upperportion 134 and the lower portion 136, the thickness of the common layer132 is partially thinned to increase an electric resistance of thecommon layer 132.

A common electrode 138 is disposed on the organic electroluminescentfilm 130. The common electrode 138 is a cathode. A voltage is applied tothe pixel electrodes 118 and the common electrode 138 to inject holesand electrons into the organic electroluminescent film 130 from thepixel electrodes 118 and the common electrode 138. The injected holesand electrons are coupled with each other in the light emitting layer toemit light. Since the insulating layer 122 is interposed between theends of the pixel electrodes 118 and the common electrode 138, theshort-circuiting between the pixel electrodes 118 and the commonelectrode 138 is prevented.

According to this embodiment, the thickness of the common layer 132 ispartially thinned above the areas between the respective adjacent pixelelectrodes 118 to increase the electric resistance. With thisconfiguration, a current can be prevented from being leaked between therespective adjacent pixels through, the common layer 132.

A sealing film. 140 is disposed on the common, electrode 138. Thesealing film 140 seals the organic electroluminescent film 130 so as toblock moisture. A filter layer 142 is disposed, on the sealing film 140.

A second substrate 144 is arranged to face the first substrate 110 witha gap. A color filter layer 146 is disposed on a surface of the secondsubstrate 144 on the first substrate 110 side. The color filter layer146 includes a black matrix 148 and a colored layer 150. Since the lightemitting layer (not shown) of the above-mentioned organicelectroluminescent film 130 emits a single color (for example, white),the provision of the color filter layer 146 enables full color displayin this embodiment. When the organic electroluminescent film 130includes plural light emitting layers that emit respective different,colors (for example, red, green, and blue), the light emitting layeremits the light of plural colors, thereby making the colored layer 150unnecessary. The filter layer 142 is disposed between the firstsubstrate 110 and the second substrate 144.

FIGS. 11 to 14 are diagrams illustrating a method of manufacturing theorganic electroluminescent display device according to the second,embodiment, of the present invention.

As illustrated in FIG. 11, the first substrate 110 on which the pluralpixel electrodes 118 are disposed is prepared, and an insulatingmaterial 152 is disposed to cover the plural pixel, electrodes 118.

As illustrated in FIG. 12, the insulating material 152 is formed into aconcavo-convex shape. For example, the concavo-convex shape is given theinsulating material 152 by nanoimprint. In detail, a nanostamper 154having fine irregularities is pushed against the insulating material 152to transfer a pattern of the nanostamper 154. In thermal nanoimprint,the Insulating material 152 is a thermoplastic resin, and theirregularities of the nanostamper 154 are pressed and transferred to theresin softened by heating to a glass transition temperature or higher.

As illustrated in FIG. 13, the insulating material 152 is partiallyremoved from above at least a center portion of the respective pixelelectrodes 118. The partial removal of the insulating material 152 isconducted by at least one of photolithography and dry etching. With theapplication of the photolithography, as illustrated in FIG. 13, an uppersurface of the remaining insulating material 152 is formed into a convexcurve shape. In this way, the insulating layer 122 is formed in theareas between the respective adjacent pixel electrodes 118 so as to reston the ends of the respective pixel electrodes 118. The insulating layer122 has the upper surface with the concavo-convex shape having theplural concave portions 124 and the plural convex portions 126.

As illustrated in FIG. 14, the organic electroluminescent film 130 isformed over the first substrate 110 with the inclusion of the commonlayer 132 that continuously covers the plural pixel electrodes 118 andthe insulating layer 122. Since the organic electroluminescent film 130is formed by vapor deposition, the organic electroluminescent film 130is shaped according to an underlying surface shape. In detail, theabove-mentioned common layer 132 is formed with the provision of theupper portion 134 resting on the respective plural convex portions 126of the concavo-convex shape of the insulating layer 122, and the lowerportion 136 resting on the respective plural concave portions 124thereof. The upper portion 134 and the lower portion 136 are offsetvertically from each other. At least parts of the upper potion 134 andthe lower portion 136 in the thickness direction thereof arediscontinuous from each other in the thickness direction. The commonelectrode 138 is formed on the organic electroluminescent film 130.

According to this embodiment, the thickness of the common layer 132 ispartially thinned above the areas between the respective adjacent pixelelectrodes 118 to increase the electric resistance. With thisconfiguration, a current can be prevented from being leaked between therespective adjacent pixels through the common layer 132.

FIG. 15 is a cross-sectional view of an organic electroluminescentdisplay device according to a third embodiment of the present invention.In this embodiment, a concavo-convex shape of an insulating layer 222 isformed on a plane. That is, bottom surfaces of plural concave portions224 are arrayed along-one plane, and upper surfaces of plural convexportions 226 are arrayed along another plane. Plural sealing films 240(a first sealing film 256, a second sealing film 258, and a thirdsealing film 260) are disposed on a common electrode 238. The sealingfilms 240 seal an organic electroluminescent film 230 to block moisture.The other configurations correspond to the contents described in theabove embodiments.

FIGS. 16 and 17 are diagrams illustrating a method of manufacturing theorganic electroluminescent display device according to the thirdembodiment of the present invention.

As illustrated in FIG. 16, a concavo-convex shape is given an insulatingmaterial 252 formed to cover plural pixel electrodes 218 by nanoimprint.In detail, a nanostamper 254 having fine irregularities is pushedagainst the insulating material 252 to transfer a pattern of thenanostamper 254. In optical nanoimprint, the insulating material 252 isa photocurable resin, and the irregularities of the nanostamper 254 arepressed and transferred to the resin, and the resin is irradiated withultraviolet rays, and cured.

Also, the insulating material 252 is recessed and thinned above atleast, the center portion of the respective pixel electrodes 218 bynanoprint. In detail, the nanostamper 254 has protrusion areascorresponding to positions at which the insulating material 252 isrecessed. The nanostamper 254 has irregularities in the relativelyrecessed areas.

Then, the insulating material 252 is partially removed from above atleast a center portion of the respective pixel electrodes 218 (refer toFIG. 15). The partial removal of the insulating material 252 isconducted by dry etching.

As illustrated in FIG. 17, the organic electroluminescent film 230 isformed. As illustrated in FIG. 15, the common electrode 238 is formed onthe organic electroluminescent film 230 to form the plural sealing films240 (the first sealing film. 256, the second sealing film 258, and thethird sealing film 260). The subsequent processes correspond to thecontents described in the second embodiment.

FIG. 18 is a diagram illustrating a modification of the thirdembodiment. Also, in this example, a common layer 332 of an organicelectroluminescent film 330 has an upper portion 334 that rests onconvex portions 326 of an insulating layer 322, and a lower portion 336that rests on a concave portion 324. However, the upper portion 334 andthe lower portion 336 are separated from each other. That is, the upperportion 334 and the lower portion 336 are offset vertically from eachother, and the overall portion of the upper-portion 334 and the lowerportion 336 in the thickness direction is discontinuous from each other.If the common layer 332 is thinly formed, the upper portion 334 and thelower portion 336 are separated from each other.

While there have been described what are at present considered to becertain embodiments of the invention, it will be understood that variousmodifications may be made thereto, and it is intended that the appendedclaims cover all such modifications as fall within the true spirit andscope of the invention.

What is claimed is:
 1. An organic electroluminescent display device,comprising: a substrate; a plurality of pixels on the substrateincluding a plurality of pixel electrodes on the substrate,respectively; an insulating layer separating the pixels from each otherand covering an end of each of the pixel electrodes; an organicelectroluminescent film above the pixel electrodes and the insulatinglayer, the organic electroluminescent film including a common layercontinuously overlapping the pixel electrodes; and a common electrodedisposed on the organic electroluminescent film and being in physicalcontact with the common layer, wherein the common layer has firstportions and second portions which are different from the firstportions, each of the first portions is located between the pixelelectrodes, electric conductivity of the first portions is lower thanelectric conductivity of the second portions.
 2. The organicelectroluminescent display device according to claim 1, wherein thefirst portions do not overlap the pixel electrodes.
 3. The organicelectroluminescent display device according to claim 1, furthercomprising a sealing film and a mask film which cover the commonelectrode, wherein the first portions do not overlap the mask film, andthe seconds portions overlap the mask film.
 4. The organicelectroluminescent display device according to claim 3, wherein the maskfilm is made of titanium oxide.
 5. The organic electroluminescentdisplay device according to claim 3, wherein the mask film is made of amaterial through which an energy ray does not pass.
 6. The organicelectroluminescent display device according to claim 3, wherein the maskfilm is located between the sealing film and the common electrode. 7.The organic electroluminescent display device according to claim 3,wherein the mask film is located on an opposite side of the sealing filmfrom the common electrode.
 8. An organic electroluminescent displaydevice, comprising: a substrate; a plurality of pixels on the substrateincluding a plurality of pixel electrodes on the substrate,respectively; an insulating layer separating the pixels from each otherand covering an end of each of the pixel electrodes; an organicelectroluminescent film above the pixel electrodes and the insulatinglayer, the organic electroluminescent film including a common layercontinuously overlapping the pixel electrodes; and a common electrodedisposed on the organic electroluminescent film, wherein the insulatinglayer has an upper surface with a concavo-convex shape having aplurality of concave portions and a plurality of convex portions, thecommon layer includes an upper portion overlapping one of the convexportions, and a lower portion overlapping one of the concave portions,the common layer has a thin region which is thinner than the upperportion and the lower portion.
 9. The organic electroluminescent displaydevice according to claim 8, wherein the common electrode is on and inphysical contact with the common layer.
 10. The organicelectroluminescent display device according to claim 8, wherein theupper portion and the lower portion are offset vertically from eachother.
 11. The organic electroluminescent display device according toclaim 8, wherein electric resistance of the thin region is higher thanelectric resistance of the upper portion and electric resistance of thelower portion.
 12. The organic electroluminescent display deviceaccording to claim 8, wherein the upper portion and the lower portionare separated from each other.
 13. The organic electroluminescentdisplay device according to claim 8, wherein bottom surfaces of theplurality of concave portions are arrayed along one plane, and uppersurfaces of the plurality of convex portions are arrayed along anotherplane.
 14. The organic electroluminescent display device according toclaim 8, wherein bottom surfaces of the plurality of concave portionsare arrayed along one convex curve, and upper surfaces of the pluralityof convex portions are arrayed along another convex curve.
 15. Theorganic electroluminescent display device according to claim 8, whereinthe thin region is located between the upper portion and the lowerportion.